If you paid for extra Google storage space (shared across Gmail, Google Docs, and Picasa) before the company introduced Google Drive on April 24, you're in great luck. That move gets you a huge discount too on its new file storage tool Google Drive.

When Google introduced Google Drive, the company increased some of the free storage limits. Now instead of 7+GB of Gmail, users have 10GB. Instead of 1GB allowed for uploaded Google Docs, you have 5GB of free storage in Google Drive.

That is, unless you paid for extra storage before April 24.

Last year I had paid for an extra 20GB of space for $5 and yesterday found 25GB of storage space in Google Drive instead of 5GB—a nice surprise. Under the new plan, 25GB of Google Drive storage space would cost $2.49 a month. (For comparison's sake, Dropbox's lowest plan, for 50GB, costs $9.99 a month and 30GB of SugarSync space costs $4.99 a month.)

You can see how much space you have available by clicking on the Google Drive app on your computer as in the screenshot above or going to http://drive.google.com/settings where you'll be told how much storage space you're currently allotted and using.

If you had paid for extra Google storage too, you can keep your old plan and this extra Google Drive storage space by: keeping your account active, keeping your Google Wallet payment information up to date, and not upgrading or canceling your current plan. Otherwise, you'll be switched to the new Google storage plan, which is much less attractive if you do the math (see the pricing structure comparison on Google below).